'Death test' claims hyped

The Sunday Times has sparked a UK media frenzy by featuring a front page report claiming that scientists are creating a device that can "tell people how long they have left to live".

The Daily Mail has suggested that the "wristwatch-style device" could even influence how insurance and pension companies calculate premiums and pay outs.

The "death watch" is said to work by using "laser beams to analyse crucial cells lining blood vessels under the skin".

The technique has been developed by physicists from Lancaster University, who are now reportedly developing a device that could be worn on the wrist. The press reports that they hope to obtain funding to get the device "on the market within three years".

The device is designed to assess one aspect of the ageing process by looking at the lining of our blood vessels. Stiffness of the arteries is linked to coronary heart disease and high blood pressure. The current device assesses stiffness in smaller vessels in the limbs, and it is plausible that it could be an indicator of ageing or vascular health.

However, it is not clear whether it is a better measure of cardiovascular health than other available measures. Also, vascular health is not the only measure of physical health, nor is it the only predictor of longevity.

It seems unlikely that this device in its current form would be able to indicate accurately when a person may die, as there is a vast variety of possible causes of death, many of which are unrelated to cardiovascular health.

Cardiovascular risk

The media fails to communicate that there are existing methods that are used by doctors in estimating your risk of developing cardiovascular disease. They usually rely on common tests that have been developed using statistical modelling based on years of research into these diseases.

One widely used method is called the Framingham Risk Score. This is used to estimate a person’s risk of developing cardiovascular disease or events, such as a heart attack, in the following 10 years. This is based on looking at individual risk factors such as age, smoking history, cholesterol levels and blood pressure.

Doctors may use this score to help them make decisions such as who could most benefit from being targeted for preventative measures.

What’s the basis of these reports?

The reports don’t appear to be based on a specific publication, rather the ongoing work of the researchers at Lancaster University. The researchers have patented a device, currently called an “endotheliometer” for assessing the endothelial cells that form the inner lining of the blood vessels. This device seems likely to be the basis of these reports.

The Mail Online suggests that there have been tests in 220 healthy volunteers. This figure seems to be based on a well-worded but rather premature press release from the University of Lancaster (published in May), which said that the research involved 200 people.

A submission from the researchers to one of the funders of the research (the Economic and Social Research Council) describes research on 80 healthy volunteers. The press release also says that the researchers are setting up a company to develop the endotheliometer.

How does the device work?

Based on the patent application, the device appears to be attached to the body, and uses a laser to monitor continuously the stiffness of the endothelial walls of the blood vessels in a non-invasive way. This device appears to have been developed after the researchers found that endothelial stiffness in the smaller blood vessels increased with age in a study of healthy volunteers from a range of ages. Vessel wall stiffness in larger arteries has been suggested to be an indicator of the health of the blood vessels and the cardiovascular system.

The news reports suggest that the device may be used to suggest if a person has cancer and dementia. However, it is not clear whether this is based on research with the device in people with these diseases, or is just a theoretical possibility.

Can this technique accurately predict time of death?

No. The Daily Mail itself states that “once the test has been refined, [the scientists] claim it should eventually be possible to tell a person how many years they have left”. So even if the device can currently tell us something about our vascular health, at the moment it certainly can’t predict when a person will die. Given the complex nature of human health, and the vast variety of different possible causes of death, it seems unlikely that this device will be able to pinpoint accurately when we will die.

This device may be able to measure endothelial stiffness accurately, but studies will need to show to what extent it can predict or help to predict a person’s future health or likely longevity. Another important question for these studies to address is whether the information produced by the device is helpful to doctors or the individual themselves in improving their health.